Analysis of the temporal and spatial scales of soil erosion and transport in a mountain basin

Abstract

Analysis of erosive processes and sediment transport in mountain environments has numerous implications for proper river basin management, land use planning as well as flood risk evaluation. Temporal and spatial scales of these phenomena may vary greatly during intense precipitation events with respect to normal conditions, thus introducing significant differences between long- and short-term related sediment yield and transport. In this work, the Erosion Potential Method is applied to Alpine catchments located in Northern Italy. Method downscaling in space and time is proposed to estimate an event-related sediment yield rather than an annual one. Interpretation of the results suggests that the long-term sediment accumulation could control the volumes transported during a single storm. Thus, some considerations on the estimation of long-term related sediment yield are further introduced. Finally, a ‘chain’ routing pattern of sediment yield through consecutively positioned basins is suggested as an alternative to a simple sum of the eroded volumes of all contributing basins when a subdivision of the catchment is adopted. Emphasis is put on the validity of the result with respect to the classical application of the method as well as on its usefulness for an integrated assessment of hydro-geological flood risk.